HP Caliper User's Guide

How traps Metrics Are Obtained
HP Caliper obtains traps metrics using the execution trace buffer (ETB) of the
performance monitoring unit (PMU). The ETB is configured to capture all changes
to/from privilege level 0.
HP Caliper takes samples by using the overflow of one of the PMU's event counters
as a sampling trigger. Samples are taken every Nth PMU event, where both N and the
sampling event are defined in the traps measurement configuration file in the HP
Caliper home directory in the config subdirectory. You can override the value in the
measurement configuration file by using the -s option.
HP Caliper attributes a sample to a trap by checking which offset into the interruption
vector table (IVT) the target branches to. HP Caliper gets the IVT start address from
perfmon on HP-UX and by reading kallsyms on Linux.
traps Measurement Report Description 297